Liquid crystal displays (LCDs) are in general light valves. Thus, to create an image they must be illuminated. The elementary picture areas (pixels, sub-pixels) are created by small area, electronically addressable, light shutters. In conventional LCD displays, color is generated by white light illumination and color filtering of the individual sub-pixel light transmissions that correspond to the individual Red, Green, and Blue sub-images. More advanced LCD displays provide programmability of the backlight to allow motion blur elimination through scrolling of individual pulsed lights. For example, scrolling can be achieved by arranging a number of cold cathode fluorescent lamps such as the LCD display in U.S. Pat. No. 7,093,970 (having approximately 10 bulbs per display) in a manner such that the long axis of the lamps is along the horizontal axis of the display and the individual lamps are activated in approximate synchronism with the vertically progressive addressing of the LCD displays. Alternatively, hot filament fluorescent bulbs can be employed and can likewise be scrolled, with the individual bulbs progressively turning on and off in a top-to-bottom, cyclic manner, whereby the scrolling can reduce motion artifacts. Known LCDs which can utilize scrolling can have a configuration similar to that shown is FIG. 1. The backlighting lamps 58 are positioned before a diffuser 51. Following the diffuser 51 is a polarizer 52 and a circuit plate 53 having address circuits and associated first surface pixel electrodes on a first glass substrate plate. The device further includes the liquid crystal material (LC) 54 positioned after the circuit plate 53. The LCD display also includes a second glass plate 55 supporting second Surface electrodes, a color filter 59, a second polarizer 56 and a surface treatment film 57, as shown and ordered in FIG. 1.
A further improvement to the standard LCD technology can be obtained by utilizing LEDs (Light Emitting Diodes) for the backlights. By arranging such LEDs in a uniformly distributed manner behind the liquid crystal material and providing three sets of LEDs (Blue, Green, and Red) that comprise the entire backlighting system, additional programmability and additional performance gains can be obtained. Key features of such LED illuminators include superior black levels, enhanced dynamic range, and also the elimination of the color filter 59 indicated in FIG. 1. The color filter 59 can be eliminated by operating the backlight and the LCD in a color field sequential manner. While LED backlights can provide excellent image characteristics, their costs are high.